/Engine/Source/Runtime/Engine/Public/SaveGameSystem.h
Gets a list of all known saves if the platform supports it. Default implementatino runs blocking version on a background thread
virtual void GetSaveGameNamesAsync ( [FPlatformUserId](API\Runtime\Core\Misc\FPlatformUserId) PlatformUserId, [FSaveGameAsyncGetNamesCallback](API\Runtime\Engine\ISaveGameSystem\FSaveGameAsyncGetNamesCallback) Callback )